Furosemide 10 mg/mL Oral Suspension

Loyd V. Allen, Jr., PhDProfessor EmeritusCollege of Pharmacy, University of OklahomaOklahoma City

US Pharm. 2017;42(2):48-49.

Method of Preparation:Calculate the quantity of each ingredient for the amount to be prepared. Accurately weigh or measure each ingredient. Mix the furosemide powder with a small quantity of SyrSpend SF Alka or simple syrup to form a smooth paste. Geometrically, add the SyrSpend SF Alka or simple syrup to final volume, mixing well after each addition. Package and label.

Use: Furosemide is used to treat edema associated with a number of disorders, including congestive heart failure, nephrotic syndrome, and hepatic cirrhosis; it also has been used as an adjunct in the treatment of acute pulmonary edema.

Packaging:Package in tight, light-resistant containers.1

Labeling:Keep out of reach of children. Shake well. Store in a refrigerator. Discard after ____ [time period].

Stability:A beyond-use date of 14 days when stored in a refrigerator may be used for this preparation made with SyrSpend SF Alka or syrup NF.1,2

Discussion:Furosemide (Lasix, Frusemide, C12H11ClN2O5S, MW 330.74) is a sulfonamide-derivative loop diuretic that inhibits the Na-K-2Cl cotransporter in the thick ascending limb of the loop of Henle. Furosemide is a fine, white to slightly yellow, odorless, practically tasteless, crystalline powder with a pKa of 3.9, and it melts at about 203°C-205°C with decomposition. Chemically, furosemide is 4-chloro-N-furfuryl-5-sulfamoylanthranilic acid. Furosemide is practically insoluble in water or dilute acids. It is freely soluble in solutions of alkali hydroxides and sparingly soluble in alcohol. Furosemide is subject to photodegradation by several mechanisms; consequently, it should be preserved in light-resistant containers. This photodegradation is minimized at pH 7, and the degradation rate increases as the pH becomes more acidic or basic. Furosemide should be packaged in well-closed containers and stored at room temperature, with excursions permitted between 15°C and 30°C, and it should be protected from light. The injection has a pH in the range of 8.0 to 9.3 and contains not more than 3.6 USP EU per mg of furosemide.1

If the source of the active drug is tablets, Lasix tablets for oral administration also contain lactose monohydrate NF, magnesium stearate NF, starch NF, talc USP, and colloidal silicon dioxide NF. The white Lasix tablets for oral administration are available in dosage strengths of 20, 40, and 80 mg. Tablets, if used, must be thoroughly pulverized before incorporation into the vehicle. To obtain 1 gram of the drug from tablets, from 12.5 to 50 tablets may be required depending on which strength is used. The 80-mg strength is preferred; obviously, the use of fifty 20-mg tablets would yield a large quantity of powder, resulting in some thickening of the preparation.

SyrSpend SF Alka is a dry powder for reconstitution. SyrSpend SF Alka provides a reasonable solution for preparing oral liquid dosage forms with acid-labile active pharmaceutical ingredients, including furosemide. It is preservative-free and alcohol-free and is suitable for problematic patients, such as neonates. SyrSpend SF Alka also allows for direct compounding in the dispensing container for maximum efficiency if the prescription or order requires 100 mL. Smaller or larger volumes may be feasible with some manipulation. SyrSpend SF Alka is buffered to pH levels >7 for acid-labile active pharmaceutical ingredients. It is preservative-free and unflavored, and it is available in a dispensing container with preweighed powder to make 100 mL (contains 6.3 g powder) or 200 mL (contains 12.6 g powder).4

Syrup (simple syrup) is a clear, sweet vehicle used as a sweetening agent and as the base for many flavored and medicated syrups. It contains 85% w/v sucrose in water and has a specific gravity of not less than 1.30. Syrup is generally self-preserving as long as the sucrose concentration is maintained sufficiently high. However, syrup NF contains a preservative unless it is used when freshly prepared. It is preferable to prepare syrup NF without the use of heat, but it may be prepared with boiling water. It should be stored in tight containers, preferably in a cool place. The pH is in the range of 6.5 to 7.5